High Energy Harvesting Performance in Piezoelectric Composite Films Employing Large Piezoelectric Fillers and Interface Engineering

Previous piezoelectric energy harvesters usually employ flexible composite films based on nanosized piezoelectric fillers. In this work, large piezoelectric particles with micron sizes were used to prepare high-performance piezoelectric composite films after forming a polydopamine (PDA) shell on the particles and introducing them into a flexible polydimethylsiloxane (PDMS) matrix. The large piezoelectric fillers contribute to a high property but are difficult to achieve a homogeneous distribution. The PDA shell can afford tight interface bonding between piezoelectric fillers and the matrix and lead to the homogeneous distribution of large fillers even if the filler content is >50 wt %. The validity was verified in different piezoelectric energy harvesters based on large-particle Pb(Zr, Ti)O3/PDMS and (Ba, Ca)(Ti, Zr)O3/PDMS composite films. These composite films show superior mechanical, ferroelectric, piezoelectric, and energy harvesting performances after PDA modification. A high output current of ∼250–390 nA can be obtained in relevant piezoelectric harvesters under a low stimulating force of 2–10 N. The obtained current under unit force exceeds the results of most previous piezoelectric energy harvesters. This work affords a general strategy to obtain high-performance piezoelectric energy harvesters based on large piezoelectric fillers and PDA modification.